This invention relates generally to tamper-evident closures for containers, and more particularly to closure constructions of the type which employ breakable strips or lugs which are intended to rupture in the event that the container is tampered with, prior to purchase or initial use by the consumer.
Various arrangements have been proposed and produced, for indicating that a particular container may have been tampered with.
U.S. Pat. No. 3,455,478 illustrates one approach, which is typical of that employed by a number of others, namely providing a closure cap with a collar that is connected to the cap by thin, frangible webs or bridges which are intended to break upon removal of the cap. In this patented construction, the collar has an internal bead which, during assembly, is forced over a cooperable external bead on the neck of the container. The collar is thus permanently retained on the container even after the cap is removed by the consumer.
A somewhat similar arrangement is shown in U.S. Pat. No. 3,673,761, except in this latter device, instead of employing a fixed internal bead on the collar, following installation of the cap and collar, the lower edge portion of the latter is heated and thereafter rolled over an external bead on the container neck.
Many of the dispensers in use today involve two-part caps, one part normally referred to as a base cap part or cap body, and being adapted to be permanently retained on the neck of the container, and the other part, commonly known as the screw cap part, being capable of being unscrewed from the base cap part or cap body. The necessity for employing this type of construction is that it is often difficult to mold a container with a relatively complex neck configuration of a type that could accept certain screw caps directly. As a result, the neck of the container is provided with a relatively simple configuration, such as a retention bead, which can cooperate with a mating retention structure on the base cap part or cap body. The arrangement between the base cap part and the container is usually such that a strong and permanent retention is had. This is usually accomplished by providing suitable cooperable bead structures as mentioned above, or by screw thread arrangements associated with locking ratchet teeth, etc. In practically all cases, such a construction discourages attempts to remove the base cap part or cap body from the container neck.
Problems have been encountered, however, in providing a container which would indicate tampering involving attempted removal of a screw cap from the base cap or cap body. Since the screw cap and cap body are not capable of being molded as a single piece, especially where screw threads are involved, the use of break-away strips has not, to my knowledge, been successful. The employment of glues or adhesives is considered to be too time consuming and messy, as well as not providing a reliable bond.